The answer is that in fact social groups have the following types:
A group that meets to discuss a class project would be a primary group on the basis of contact.
<em>This is based on contact (C.H. Cooley)</em>
- Primary group
- Secondary group
A group that meets to discuss a class project would be an in-group on the basis of identification.
<em>This is </em><em>based on Identification</em><em> (W.G. Sumner)</em>
- In-group
- Out-group
A group that meets to discuss a class project would be either a formal group or an informal group on the basis of rules and regulations depending on how strict the rules are but a study group is most likely an informal group.
<em>This is based on rules and regulation.</em>
- Formal group
- Informal group
A group that meets to discuss a class project would either be a voluntary group on the basis of structure.
<em>This is based on structure (Dwight Sanderson)</em>
- Voluntary group
- Involuntary group
- Delegate group
A group that meets to discuss a class project would be a pro-social group on the basis of relation to society.
<em>This is based on </em><em>relation to society</em><em> (George Hassen)</em>
- Un-social group
- Pseudo-social group
- Anti-social group
- Pro-social group